September 1966 



COMMERCIAL FISHERIES REVIEW 



77 



exceed the capacity of the area's canneries, 

 the Governor of Alaska invited the Japanese 

 to purchase the surplus fish. As a result. 



five Japanese stern trawlers,* already oper- 

 ating in the Gulf, were dispatched to Cook 

 Inlet to buy and freeze salmon. 



MAN MAY OWE HEARING TO ANCIENT FISH 



Man may be indebted to a 350-million-year-old fishforhis ability to hear today. Some 

 members of an ancient family of fish, called Eusthenopteron, had an air-filled "spiracular 

 pouch" or sac in their heads which was very similar to man's middle ear, said a scientist 

 of the Bell Telephone Laboratories. These fish also must have had an outer eardrum, the 



scientist reported to the Acous- 

 tical Society of America meet- 

 ing in Boston. From estimates 

 of the size of the eardrum and 

 the air sac, he calculated that 

 the fish would have heard sounds 

 not only through the water but 

 also through the air. 



Hearing capability of a very 

 primitive sort first appeared in 

 early fish as a system of sen- 

 sory cells of the sides and head 

 that responded to water mo- 

 tions. As fish evolved, they de- 

 veloped a swim bladder, which 

 was essentially a trapped air 

 bubble changing volume under 

 the influence of pressure waves. 

 This probably functioned origi- 

 nally as a buoy or aid in respi- 

 ration, obeying the gas laws and 

 changing volume when pressure 

 changed, but incapable of lo- 

 cating any source of sound 

 waves. However, this swim bladder was close enough to affect an "inner ear" labyrinth lo- 

 cated deep inside the fish's skull. 



The swim bladder and the extensions it later developed could be considered a middle 

 ear and the labyrinth an inner ear, the scientist said. His studies on primitive hearing 

 organs of the ancient fish will provide insight into the hearing capabilities of higher ani- 

 mals including man. (Reprinted, with permission from Science News, weekly summary of 

 current science, copyright 1966 by Science Service, Inc.) 



An artist's concept of a fish and its environment that lived some 350 million years 

 ago. It is theorized that man's hearing mechanism may have evolved from this 

 species or its family. 



